Azine
Azines are a functional class of organic compounds with the connectivity RR′C=N−N=CRR′. These compounds are the product of the condensation of hydrazine with ketones and aldehydes, although in practice they are often made by alternative routes. Ketazines are azines derived from ketones.[1] For example, acetone azine is the simplest ketazine. Aldazines are azines derived from aldehydes.[2]
Preparation
[edit | edit source]The usual method of industrial production is the peroxide process, starting from the ketone, ammonia, and hydrogen peroxide.[3]
In the laboratory, azines are typically prepared by condensation of hydrazine with two equivalents of a carbonyl.[4]
Azines are also produced when chalcone reacts with a hydrazone to produce 3,5-diphenyl-1H-pyrazole,[5] in a conversion also carried out with hydrazine hydrate.[6][7]
Reactions
[edit | edit source]Azines characteristically undergo hydrolysis to hydrazines. The reaction proceeds by the intermediacy of a hydrazone:
- R2C=N−N=CR2 + H2O → R2C=N−NH2 + R2C=O
- R2C=N−NH2 + H2O → N2H4 + R2C=O
Azines have been used as precursors to hydrazones:[4][8]
- R2C=N−N=CR2 + N2H4 → 2R2C=N−NH2
They are also precursors to diazo compounds.[9][8][10]
The coordination chemistry of azines (as ligands) has also been studied.[11][12][13]
Acetone is used to derivatize hydrazine into acetone azine for analysis by gas chromatography. This method is used to determine trace levels of hydrazine in drinking water[14] and pharmaceuticals.[15]
Applications
[edit | edit source]Ketazines are also important intermediates in the industrial production of hydrazine hydrate by the peroxide process.[3] In the presence of an oxidant, ammonia and ketones react to give hydrazine via ketazine:
- 2 Me(Et)C=O + 2 NH3 + H2O2 → Me(Et)C=NN=C(Et)Me + 2 H2O
The ketazine can be hydrolyzed to the hydrazine and regenerate the ketone:
- Me(Et)C=NN=C(Et)Me + 2 H2O → 2 Me(Et)C=O + N2H4
Ketazines have been also used as sources of hydrazine produced in situ, for example in the production of herbicide precursor 1,2,4-triazole.[16]
References
[edit | edit source]- ^ IUPAC, Compendium of Chemical Terminology, 5th ed. (the "Gold Book") (2025). Online version: (2006–) "ketazines". Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ IUPAC, Compendium of Chemical Terminology, 5th ed. (the "Gold Book") (2025). Online version: (2006–) "aldazines". Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Jean-Pierre Schirmann, Paul Bourdauducq "Hydrazine" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)..
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- ^ US 6002015, Nagata, Nobuhiro; Nishizawa, Chiharu & Kurai, Toshikiyo, "Method of producing 1,2,4-triazole", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Mitsubishi Gas Chemical Co..
Further reading
[edit | edit source]- Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- US 3965097, Eichenhofer, Kurt-Wilhelm & Schliebs, Reinhard, "Production of ketazines", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Bayer.
- US 3972878, Schirmann, Jean-Pierre; Combroux, Jean & Delavarenne, Serge Yvon, "Method for preparing azines and hydrazones", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Produits Chimiques Ugine Kuhlmann.
- US 3978049, Schirmann, Jean-Pierre; Tellier, Pierre & Mathais, Henri et al., "Process for the preparation of hydrazine compounds", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Produits Chimiques Ugine Kuhlmann.
- US 4093656, Schirmann, Jean-Pierre; Combroux, Jean & Delavarenne, Serge Yvon, "Method for making azines", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Produits Chimiques Ugine Kuhlmann.
- US 4724133, Schirmann, Jean-Pierre; Combroux, Jean & Delavarenne, Serge Y., "Preparation of a concentrated aqueous solution of hydrazine hydrate", published Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value)., assigned to Atochem.